Bring a large pot of water to boil and cook macaroni according to package directions. Drain. In another large pot, heat olive oil over medium-low heat. Cook onions until brown and caramelized, 15 – 20 minutes. Transfer to a plate. Set aside.
Melt butter in the same pot that you cooked the onions in. Once melted whisk in flour. Allow to cook one minute. Stir in milk. Stir in cheese and Worcestershire. Cook until cheese has melted.
Whisk some of the warm milk into the beaten egg to temper it. Whisk the tempered egg into the cheese and milk mixture.
Stir in caramelized onions. Fold in macaroni. Mix well. Allow to set for 5 minutes or just until thickened. Spoon macaroni and cheese into serving bowls. Sprinkle with crumbled potato chips. Serve hot.
Tom Cooper | Elite.